Our Nesting Fly Boxes (with Umpqua Logo) are ingenious with nesting feet on the bottom and corresponding holes on the top that allow firm attachment. Once “nested” all boxes can still be opened individually. Ideal for separating categories of flies that can then be mixed and matched as needed for specific locations and hatches. Note: 2/3 = two compartments deep by three compartments long, for a total of six compartments.